LS PROJECT, PART 2 BLOCK PREP AND BALANCING by Mike Mavrigian all photos by author We swapped out the OE torque-plus-angle main cap bolts for a set of ARP studs. This will provide added strength and will eliminate wear on the block’s female threads during future servicing. I recently visited Gressman Powersports where Scott Gressman [...]
A precision mounting plate is installed to the rear of the block. This accurately locates the block to the machine’s base fixture. A centering bar is inserted through the main bores. The main bore centering bar is bushed to accommodate the specific block’s main bore diameter. A camshaft tunnel centering bar helps the machine to [...]
CNC-MACHINING AN ENGINE BLOCK A step-by-step overview of a specific block being machined on a CNC from start to finish. by Mike Mavrigian all photos by author CNC machines vary in terms of footprint size and axis capabilities. Thinking about taking the plunge and buying a CNC (computer numeric control) machine? Or have you wondered [...]
FORGED OR BILLET? Depending on who you talk to, some say that forgings are stronger than billets and some say just the opposite. We’re not going to debate that issue here. One of the indisputable benefits derived from carving cranks from billet bar stock is versatility since by simply writing the appropriate program, you can [...]
Custom pistons are available in any configuration, but knowing what’s needed to order them requires careful measurement and sound decisions. Once the data sheet is accurately completed, your order begins to forge blank slugs. Initial machining begins with pin bore placement. Here the rod small end passage is machined, based on your reported small end [...]
ORDERING CUSTOM PISTONS When an off-the-shelf slug won’t do, you need to turn to the custom boys. by Mike Mavrigian photos by author Need a set of custom slugs to work with your new heads and your bore/stroke combo? A ton of info is required before a piston manufacturer can begin to execute your order. [...]
CYLINDER BORE DISTORTION Understanding static and dynamic cylinder bore shape. by Mike Mavrigian All illustrations courtesy Mahle-Clevi This stress graph illustrates how a cylinder bore may be distorted from round to out-of-round as a result of head fastener loads. This dimensional “isometric” view further illustrates static dimensional shift that can occur from cylinder head installation. [...]
HOW DO I USE THE MACHINE? If you opt for a “universal” CNC machine, you’ll need extensive training to learn the computer “coding” language required to create programs. However, if you choose a CNC machine that was designed specifically for use by engine builders, operation and the overall learning curve is much simplified, since programs [...]
COMPUTER-AIDED BLOCK MACHINING by Mike Mavrigian One of the prime benefits of owning a CNC machine is the capability of accurizing an engine block to “blueprint” specifications in terms of correct centerline placements. (photo courtesy Sunnen) A full-blown CNC machining center, such as this Sunnen/RMC V40, expands shop capabilities to include not only block and [...]
HONING THE CYLINDERS Following a recommendation from our buddies at Sunnen, we visited Gressman at Gressman Powersports in Fremont, Ohio (Gressman has built a number of 632 motors, in addition to countless big-number drag, sprint car and road-race engines). Naturally, the Ohio winter weather forced us to drive in sub-zero temperatures. Even with the block [...]
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